Rotary electric machine having laminated armature core

Abstract

An armature composed of a shaft and an armature core is rotatably supported in a housing of a rotary electric machine. The shaft is forcibly inserted into a center hole of the armature core formed by laminating core sheets. Each core sheet has a center hole and outer holes connected to the center hole. A contour of the center hole is not continuous because the outer holes are connected thereto. The shaft can be firmly connected to the laminated core sheets with a relatively low inserting force. The shaft has a smooth outer surface having no knurls or the like. In addition, the outer holes of the laminated core sheets form cooling air passages in the armature core in its axial direction.

1. A rotary electric machine, comprising:
 a housing; and 
 an armature having a shaft rotatably supported in the housing and an armature core fixedly connected to the shaft, wherein: 
 the armature core is formed by laminating a plurality of core sheets, each core sheet having a center hole and outer holes connected to the center hole with no intervening material therebetween wherein the core sheets are laminated so that the outer holes of the core sheets communicate with one another, thereby forming air passages in the armature core in the axial direction thereof, and the laminated core sheets are divided into a predetermined number of blocks; and the outer holes of the core sheets are positioned at a same position in each block and are shifted block by block by a predetermined angle around the axial direction, thereby forming air passages skewed block by block relative to the axial direction in the armature core. 
 
   
   
     2. The rotary electric machine as in  claim 1 , wherein:
 the core sheets are laminated so that the outer holes of the core sheets are positioned in a shifted relation to one another by a predetermined angle around the axial direction, thereby forming air passages skewed relative to the axial direction. 
 
   
   
     3. The rotary electric machine as in  claim 2 , wherein:
 the plurality of core sheets are laminated by dividing the same into a few blocks. 
 
   
   
     4. The rotary electric machine as in  claim 2 , wherein:
 the predetermined angle is an angle corresponding to one slot pitch. 
 
   
   
     5. The rotary electric machine as in  claim 1 , wherein:
 the predetermined angle is an angle corresponding to one slot pitch. 
 
   
   
     6. The rotary electric machine as in  claim 1 , wherein:
 the armature further having conductor segments, each conductor segment including an in-slot portion disposed in a slot formed on an outer periphery of the armature core and a coil end bent from the in-slot portion and disposed on an axial end surface of the armature core; and 
 the coil ends of the conductor segments are circularly arranged on the axial end surface of the armature core, thereby forming a commutator surface that contacts brushes. 
 
   
   
     7. The rotary electric machine as in  claim 1 , wherein:
 the armature further having conductor segments, each conductor segment including an in-slot portion disposed in a slot formed on an outer periphery of the armature core and a coil end bent from the in-slot portion and disposed on an axial end surface of the armature core; and 
 the coil ends of the conductor segments are circularly arranged on the axial end surface of the armature core, thereby forming a commutator surface that contacts brushes. 
 
   
   
     8. A rotary electric machine, comprising:
 a housing; and 
 an armature having a shaft rotatably supported in the housing and an armature core fixedly connected to the shaft, wherein: 
 the armature core is formed by laminating a plurality of core sheets, each sheet having a center hole and outer holes connected to the center hole, the laminated core sheets being divided into a predetermined number of blocks, the outer holes of the core sheets being positioned at a same position in each block and shifted block by block by a predetermined angle around the axial direction, thereby forming air passages skewed block by block relative to the axial direction in the armature core; and 
 the armature core is connected to the shaft by forcibly inserting the shaft into the center holes of the laminated core sheets. 
 
   
   
     9. The rotary electric machine as in  claim 1 , wherein an outer surface of the shaft contacting the center holes of the laminated core sheets has no knurls.